Thermostat for controlling furnaces.



L. A. LARSON. THERMOSTAT FOR CONTROLLING FURNACES.

APPLICATION FILED JUNE 29 1912.

Patented Aug. 5, 1913} 2 SHEETSSHEET 1.

, .[IllfTLZOIZ liq his Aitomw Witnesses,

L, A. LARSON. THERMOSTAT FOR CONTROLLING FURNACES.

' APPLICATION FILED JUNE 29, 1912. I v A L6 438 Patented Aug. 5, 1913.

2 SHEETS-SHEET 2.

W QL 6 w a ww lit) LOUIS ANDREW LARSON, OF 'lVlINNEAPOLIS, MINNESOTA.

THERMOSTAT FOR- CONTRQLLING FURNACES.

ooms Specification of Letters Patent.

Application filed June 29, 1912. Serial No. 706,881.

to which it appertains to'make and use the same.

Particularly, my invention has for its ob-.

ject to provide an improved weight motor adapted for use in connection with automatic heat regulators but the improved motoris capable of general use wherever there is desired an int-ermittentlyacting movable force.

Generally stated, the lnvention consists of the novel devices and combinatlons of devices hereinafter described and defined inthe claim.

1n the accompanying drawings which illustrate the invention, like characters indicate like parts throughout the several views.

Referring to the drawings, Figure 1 is a view in front elevation with some parts broken away and some parts removed sl1OW ing the improved motor and illustrating, diagrammatically, a thermostat, and elcctrical connections between the thermostat and motor; Fig. 2 is a detail view in front elevation with some parts broken away, showing a part of the motor case and the fixed contacts of the thermostat circuit;

Fig. 3 is a detail in'elevation looking atthe motor case from the left toward .the right, in respect to Fig. 1; Fig. 4 is a section taken on the line w 'm on Fig. 1; Fig. 5 is a detail section on the line 0: m on 1, some parts being removed. Fig. 6 is a section taken on the line 00 ac on Fig. 4 some parts being removed; Fig. 7 is a detail view in horizontal section taken centrally through the so-called contact ring and cooperating driving wheel; Fig. 8 is a fragmentary view in elevation, showing the so-called.contact ring; and Fig. 9 is a horizontal section on the line 03 00 on Fig. 8.

' Preferably, most of the elements'of the motor proper arecontained Within a suitcase 1, one side of which is removed in Fig. 1. I

The numeral 2 indicates a crank shaft which is extended through the case 1, prurnaledun the sides thereof. and at its projecting ends is provided with crank arms 3 that project diametrically in opposite directions. These crank arms 3 operate alternately to open and close the draft and check dampers of a furnace, not shown, through suitable connections 4- attached to the re spcctive crank arms 3. The shaft 2 operates .as a working shaft, and rigidly secured thereon within the case 1 is a socalled contact wheel 5 that is provided with a concern tric contact ring 6 and with aii'eccentric contact 7. The contact ring 6 is in constant engagement with a fixed contact; 8, shown as secured to one side of the case 1; and the contact 7 is adapted to alternately engage with fixed contacts 9 and 10, also shown as secured to the same'side of the case 1. These contacts 910 are located diametrically opposite to each other inrospect to the axis of the shaft 2. The socalled contact wheel 5 is provided at diametrically op osite points'with projecting stop lugs 11, t e purpose of which will pres-- ently. appear.

Loosely journaled on the shaft 2 adjacent to the so-called wheel is "a peripheral grooved driving wheel 12, which, on thatface which is adjacent to the said contact wheel is provided with a faced toothed ratchet ring 13. For engagement with the ratchet ring 13 the contact wheel 5 is pro-' vided with a spring pressed lug 14 that constantly engagcs the teeth of said ratchet ring and cooperates therewith, to cause the driving wheel 12, when rotating the direc tion 0 the arrow marked thereon in Fig. 1, to positively rotate the said contact ring in the same direction.

The motive force for driving the wheel 12 is preferably afforded by a quite heavy weight 15, connected to one end of a driving cable 16. advisably through a coiled spring 17. This driving cable 16 is passed over the driving wheel 12 and works with very considerable frictional engagement therewith, in the diverging peripheral groove thereof. At its opposite end, the said cable is shown as provided with an end ring 18, by means of which that end of the cable may be drawn downward and the weight 15 raised whenever desired. will, of course, be understood that when the cable is thus drawn to raise the. weight the driving wheel Patented rang. 53,12,113.

ward. due to the force of the weight act 2 within the case 1.

ing thereon through the engaging contact lug 11. This movement, however, is .normally prevented by an armature 22 secured to the free end of a spring arm 2;} that is anchored to a suitable bearing 21 secured the arm 23 tends to hold the said armature 22 in its retracted normal position, shown in Fig. 1. provided with a thin brass or copper facing 22 that engages with the outer end of the escapement lever 19 and prevents sticking of the armature to the said lever under magnetic action. An electro-magnet 25, secured to a suitable support 26 within the case 1 cooperates with the armature 22, and when energized, moves the same far enough to re-' lease the outer end of the'escapement lever 19. The said escapement lever 19, however, is subject to a suitable spring 27 attached to and anchored to the supporting bar 21. This spring 27, while it normally tends to hold the said lever 19 in its operative position shown in Fig. 1, is of such a weak tension that when the force of the weight 15 is on the Inner end thereof, and the outer end thereof 18 released from the armature 22, the said lever will be rocked into a position to permit the engaging lug 11 ofthe contact wheel 5 to be carried past the same. This action will be further considered in the description of the operation. One terminal of the coil of the magnet 25 is connected by a wire 28 to the fixed contact 8, and the other terminal of said coil is connected to one load 29 of a battery or other source of electrical energy 30. The other lead 31 of the battery 30 is connected to the movable thermally actuated contact 32 of a thermostat 33 of ordinary well known construction. The other two contacts, to-wit, the outer contacts of the thermostat, are connected by leads or wires 33 and 34, respectively, to the fixed contacts 9 and 10. In the battery lead 29 (see Fig. 3), a normally closed switch 35 is preferably interposed. When this switch 35 is in open position, the thermostat is thrown out of action, but when it is closed, the thermostat is rendered operative to control the intermittent actions of the motor.

Operation: The principle upon which the thermostat controls a weight motor is well understood to all familiar with the subject. When the contact wheel 5 is stopped by en The spring tension in The armature 22 is preferably.

gagcment with one or the other of the stop lugs 11 thereof. with the escapemcnt lever 19, its contact 7 will be in engagement with one or the other of the diametrically opposite fixed contacts 9-10; and at such time, the battery circuit will be closed through the magnet 25 by movement of the thermostat contact 32 in proper direction; l/Vhen the circuit is thus closed through the magnet, the magnet will be energized and will draw the armature 25 out of engagement with the outer end of the escapement lever 19 and then t-he force of the weight 15, acting on the short inner end of said lever, through the engaging stop lug 11, will cause the latter to force the free end of the said leverupward and the inner end thereof downward, thereby permitting the said lug to move past the said escapemcnt lever. Immediately after the said lug is passed, the said escapement lever and spring 27 will throw the said lever back to its normal position, and at or about the same time, the contact 7 will move out of engagement with the fixed contact; 9 or 10, as the case may be, thereby breaking the battery circuit through the magnet with the result that the said magnet will be denergizedand the armature 22 will be thrown back into its normal position and thereby again lock the escapement lever 19 in its operative position. Under this ac' tion, a quick return of the escapement lever to its normal or operative position is insured so that it willbe sure'tointercept the other stop lug 11. In this way, at each release of the contact wheel 5, the latter will be given a half rotation under the action of the wheel 12. To'raise the weight, it is only necessary, as already stated, to pull downward on the ring 18. The spring 17 relieves the mechanism of the motor from jars or undue strains when one of the stop lugs 11 engages with the escapement lever 19. i

connection for applying a driving force to the driving wheel or corresponding rotary member.

What I claim is:

In a motor of the kind described, the combination with a working shaft and support therefor, of a driving wheel loose on said shaft, a contact wheel secured to said shaft adjacent to said driving shaft, a pawl and ratchet connection between said driving wheel and contact wheel applied to the adjacent faces thereof, a contact ring and traveling contact applied to the other face of said contact wheel, a fixed contact having continuous engagement with said contact ring, diametrically opposite fixed contacts with which the traveling contact of said contact wheel engages alternately, a thermostat having three leads. connected to the said three fixed contacts, means tending to rotate snicl driving wlm-vl. circumferenlially spaced stops on and mnlnct wln-el. an escapenn-nl' lever 1el(lmgl \fh0l(;l m an operative p051.-

tion for engagement in SIICCQSSIOII with the-' stops rm said contact wheel, an elecho-magnot, a device normally locking said escapemenl' levm' in its opcl'aiive' po'sition and in- Cllldlllf 1' jlll armature that is subject to said (-ltll-lU-lllzlgll0i, and electrical connections to said elech' -nmgiwls invluding nllui' ihv. 10

i} above noted lech'icnl contacts, substantially i as (lescrilwcl. v

' In testimony \vlm oof l :illix my signature in presence of two \vit'ncsscst'.

LOUIS'AXDRPHV LARSOX.

A HARRY vD. KILGORE. 1 

